1. Field of the Invention
This invention relates generally to telecommunications, and, more particularly, to wireless telecommunications.
2. Description of the Related Art
A conventional wireless telecommunications system, such as a cellular telephone system, includes one or more base stations (sometimes referred to as node-Bs) that may establish and/or maintain one or more concurrent wireless communication links with one or more mobile units. For example, a base station may establish and/or maintain concurrent wireless communication links with a plurality of mobile units within a cell associated with the base station. The mobile units may be cellular telephones, pagers, personal data assistants, portable computers, desktop computers, and the like.
A radio network controller may be coupled to the one or more base stations. Among other functions, the radio network controller manages resources for an uplink dedicated channel used by each mobile unit associated with each of the base stations. For example, the radio network controller may include a resource management function that controls the interference from other mobile units in the cell, as well as handover mobile units in neighboring cells, so that a required quality of service (sometimes referred to as a QoS) is satisfied for each mobile unit. As of Release 99 of the Universal Mobile Telephone Service (UMTS) protocol, allocation and coordination of dedicated channel resources between all of the base stations is carried out by the radio network controller.
The radio network controller performs the various resource management functions based upon a long-term entity such as a long-term average of the Received Total Wideband Power or Received Signal Strength Indicator, which are absolute measures of the aggregate received power. The long-term entity is typically used to determine a measure of the relative contribution of thermal noise and interference from other mobile units called the “rise-over-thermal,” or RoT. The radio network controller may use the rise-over-thermal to allocate the resources of the base stations such that a desired quality of service may be maintained for each mobile unit. For example, the radio network controller may use the rise-over-thermal to administrate the total number of the users in the system and the system load of the base stations so that a frame error rate for each mobile unit may be kept below a desired level or in a desired range. For another example, the radio network controller may use the rise-over-thermal to administrate the total number of the users and the system load of the base stations so that a signal-to-noise ratio for each mobile unit may be kept above a desired level or in a desired range.
However, the radio network controller requires additional headroom with an assumption of a worst case scenario to perform the resource management functions, which reduces the efficiency of the wireless telecommunications system. For example, the radio network controller may account for silences in voice communication, such as pauses in a conversation, by assuming a worst-case scenario in which all mobile units are assumed to be transmitting and/or receiving voice communications during silences. The additional headroom is, at least in part, a result of the radio network controller performing the various resource management functions based upon long-term variables, such as the long-term average of the Received Total Wideband Power or Received Signal Strength Indicator. Nevertheless, it is desirable to have the radio network controller perform at least some resource management functions, particularly resource management functions that involve more than one base station, such as call admission and handover control.
The present invention is directed to addressing the effects of one or more of the problems set forth above.